1. Field of the Invention
The invention relates to a derailleur guard, more particularly to a derailleur guard which can be easily assembled and disassembled from a bicycle wheel without the need for removing a sprocket cluster of the latter.
2. Description of the Related Art
Referring to FIGS. 1 and 3, a conventional rear bicycle wheel is shown to comprise a rim 11, a tire 10 mounted on the rim 11, a central hub 13 provided with a pair of annular radial flanges 130, and a plurality of spokes 12, each of which has a first end connected to the rim 11 and a second end connected to one of the radial flanges 130. A commercially available rear bicycle wheel usually has 32 or 36 spokes. A sprocket cluster 14 is mounted on one end portion of the hub 13 for engaging a bicycle drive chain (not shown). An annular derailleur guard 15 is mounted on the hub 13 and is disposed between the spokes 12 and the sprocket cluster 14.
Referring to FIG. 2, the derailleur guard 15 is formed with a central through-hole 150 that permits extension of the hub 13 therethrough. The derailleur guard 15 further has an inner face which is formed with a plurality of hook units 151. The hook units 151 are equally displaced around the periphery of the through-hole 150 and engage the outer periphery of one of the radial flanges 130 to mount the derailleur guard 15 on the hub 13, as shown in FIG. 3.
The main purpose of the derailleur guard 15 is to prevent the bicycle drive chain from falling into a clearance formed between a largest sprocket of the sprocket cluster 14 and the spokes 12 due to improper operation of the rear derailleur in order to avoid jamming of the rear bicycle wheel which can endanger the user. Thus, according to regulations issued by the American Consumer Products Safety Commission, bicycles which do not incorporate a derailleur guard cannot be exported to the United States. However, bicycles which are not manufactured in the United States are seldom provided with a derailleur guard or usually incorporate a derailleur guard that lacks aesthetic appeal, thereby necessitating the installation of a new derailleur guard.
It is noted that the sprocket cluster must be removed from the hub prior to installation of the conventional derailleur guard, thereby resulting in a great deal of inconvenience. In addition, removal of the sprocket cluster cannot be performed without the use of special tools. Thus, the user is unable to replace the derailleur guard when the latter is damaged or does not appeal to the user.